STOCKHOLM – December 21, 2012. Karolinska Development AB announced today that a syndicate led by the life science investor Rosetta Capital Limited (“Rosetta”) will acquire a minority share in Karolinska Development’s holdings in 13 of its 25 portfolio companies for SEK 220 million. A conference call will be held today at 3.00pm CET. For the purpose of the transaction, Karolinska Development will transfer 13 of its portfolio company holdings to a new private holding company (“KDev Investments AB”). The KDev Investments portfolio will include both early and clinical stage pharmaceutical assets as well as some technology assets. Rosetta will acquire 7.33% of the common shares in KDev Investments AB for SEK 110 million and preference shares in KDev Investments AB for a further SEK 110 million. The terms of the preference shares, which are set out below, provide for gradually reducing returns for Rosetta, limiting Rosetta’s upside in return for partial protection of its downside.

The consideration to be paid by Rosetta implies a total value of the KDev Investments portfolio of approximately SEK 1,500 million, about two times Karolinska Development’s investment in the same portfolio and a 23% premium to the reported fair value. After the transaction, Karolinska Development’s cash and short-term investments will be approximately SEK 500 million.

Torbjörn Bjerke, CEO of Karolinska Development:

“This deal shows the value that Karolinska Development has created in recent years. Our financial position is significantly strengthened and this will enhance our ability to build further value in both KDev Investments as well as the rest of our portfolio, by taking products onwards to the point where we can secure partnerships with pharmaceutical companies as well as trade sales of portfolio companies.”

Karolinska Development’s pro forma net asset value (NAV) which reflects the transaction with Rosetta, but is otherwise in accordance with the reported NAV as of September 30, 2012, amounts to SEK 46.3 per share, compared to SEK 40.4 prior to the transaction.

Mr. Donald Macpherson, Chairman of Rosetta Capital Limited:

“We are delighted to be investing in the Karolinska Development portfolio and are extremely impressed by the quality of the underlying science and the commercial opportunities. We look forward to significant investment returns for all stakeholders, and the development of new and innovative medical treatments for the benefit of society as a whole. Our team is delighted to have the opportunity work actively alongside the Karolinska Development team.”

Invitation to Conference Call at 3.00pm CET

Please dial in at the following number a few minutes before the start of the conference call: SE: +46 (0) 8 505 598 75, from the UK: +44 (0)20 710 862 05 or the US: +1 866 676 58 70.

About the Transaction

Karolinska Development will transfer 13 of its portfolio company holdings to KDev Investments AB in exchange for all the issued shares. Concurrently, Rosetta will acquire shares in KDev Investments AB from Karolinska Development as follows:

Karolinska Development will receive the SEK 220 million cash consideration in two tranches. The first tranche of SEK 203 million will be received on completion of the deal, planned to close on January 31, 2013, and the second tranche is due when the total accumulated return from KDev Investments AB has reached SEK 17 million.

Rosetta’s preference shares will have a priority on future returns from the entire KDev Investments portfolio as outlined below. All remaining total return is to be divided between the common shareholders, with 92.67% to Karolinska Development and 7.33% to Rosetta.

(i) 100% of the total future return up to SEK 220 million*;

(ii) 30% of the total future return between SEK 220 million and SEK 880 million;

(iii) 18.33% of the total future return between SEK 880 million and SEK 1,320 million; and

(iv) 0% of the total future return over SEK 1,320 million.

*From which Karolinska Development will receive its second tranche of SEK 17 million

The experienced Rosetta team will assist by taking additional board roles in portfolio companies, and shall be involved together with Karolinska Development personnel in the direction and management of all of the holdings in portfolio companies owned by KDev Investments AB, wherever their specific expertise can assist the company concerned.

About KDev Investments AB

Karolinska Development is the majority owner of KDev Investments AB. The shareholders of KDev Investments AB have entered into a shareholders agreement regulating the management of the company.

The KDev Investments group will become a joint venture of Karolinska Development presented at Fair value. Several existing subsidiaries in the Karolinska Development Group will be part of the KDev Investments group. As KDev Investments group is a joint venture, these companies will also be presented at Fair value. The impact on the balance sheet and income statement of Karolinska Development group resulting from this transaction will be accounted for accordingly.

About Karolinska Development AB Karolinska Development aims to create value for patients, researchers, and investors by developing innovations from world class science into products that can be sold or out-licensed with high returns. The business model is to: SELECT the most commercially attractive medical innovations; DEVELOP innovations to the stage where the greatest return on investment can be achieved; and COMMERCIALIZE the innovations through the sale of companies or out-licensing of products. An exclusive deal flow agreement with Karolinska Institutet Innovations AB, along with other cooperation agreements with leading Nordic universities, delivers a continuous flow of innovations. Today, the portfolio consists of 34 projects, of which 15 are in clinical development. For more information, please visit www.karolinskadevelopment.com.

Karolinska Development is listed on NASDAQ OMX. Karolinska Development may be required to disclose the information provided herein pursuant to the Securities Markets Act.

About Rosetta Capital

Rosetta Capital is a specialist venture capital firm focused on the life science and medical technology sectors, with a multinational team from the venture capital, pharmaceutical and biotechnology sectors. For more than 10 years, Rosetta has been working with entrepreneurs, young life science companies and investors to help them achieve their ambitions. Currently, Rosetta manages funds with holdings in more than 25 underlying portfolio companies across Europe and North America and with more than USD 200m in value. Rosetta is focused on co-investment portfolio transactions and from time to time, Rosetta also makes direct primary venture investments. Rosetta offers flexibility in transactional structure, adapting strategies to the investment climate. Rosetta is headquartered in the United Kingdom. Rosetta Capital Ltd is Authorised and Regulated by the Financial Services Authority. For more information see www.rosettacapital.com.